Histology Flashcards
What forms the capsule which covers the outer kidney?
thin but strong capsule of dense collagen fibres
How many medullary pyramids can be seen in one kidney?
8-18 per kidney
What is found at the apices of the medullary pyramids?
renal papillae
How does the blood supply get to the renal cortex?
Vessels travel up renal columns and supply cortex
Medulla of kidney is supplied VIA the cortex
What is the name given to the fat pads found at the renal hilum?
Renal Sinus
What are the two main components of the nephron?
Renal corpuscle (contains the glomerulus) Renal tubules
How many nephrons do we have per kidney?
600,000 - 1 million
What length is a nephron?
45-65mm
What is the function of the renal corpuscle?
production and collection of glomerular filtrate
What is the glomerulus?
Group of capillaries
What is Bowmans capsule?
Epithelium into which the glomerulus extends (Balloon theory)
What two layers seperate the blood from the glomerular filtrate?
- capillary endothelium
2. specialised epithelium on top of glomerular capillaries (podocytes)
What structure forms the filtration slits?
the podocytes have interdigitating cell processes (pedicels) forming filtration slits
The basal lamina between the capillary endothelium and the specialised podocyte epithelium is 6x larger than an average basal lamina. TRUE/FALSE?
TRUE
How much glomerular filtrate is produced per minute and how much of this is urine?
100-125ml/min
(but only about 1ml/min of urine).
What two poles does the renal corpuscle have?
a vascular pole,
and opposite this, a urinary pole
What is the name given to the core of the glomerulus?
mesangium (this also extends out of the glomerulus)
What are the 3 components of the glomerular filter?
fenestrated endothelium of the capillary
thick basement membrane
The filtration slits between pedicels
What is the function of the Proximal convoluted tubule?
REABSORPTION
water, proteins, amino acids, carbohydrates and glucose
What process is used to reabsorb 70% of the sodium in the proximal convoluted tubule?
active transport
What process is used to reabsorb water in the proximal convoluted tubule?
Diffusion
How are glucose and amino acids reabsorbed in the proximal convoluted tubule?
Co-transport
Describe the epithelium found in the proximal convoluted tubules
Cuboidal
Extensive brush border of microvilli
Why does the proximal convoluted tubule epithelium contain junctional complexes at the apical end?
To prevent expelled contents from diffusing back in
Describe the histological difference between proximal convoluted tubules and distal convoluted tubules?
PROXIMAL = larger than the distal convoluted tubules PROXIMAL have a less well defined luminal margin due to the brush border
The loop of Henle gets thinner as it passes the cortex/medullary junction. TRUE/FALSE?
TRUE
What is the main function of the loop of Henle?
creates the hyperosmotic (SALTY) environment in the medulla
What is the difference in epithelium between the thick and thin limb of the loop of Henle?
Thick = cuboidal epithelium Thin = Squamous epithelium
What are the vasa recta?
Thin walled blood vessels which dip down from the cortex and then climb back up to permit a highly osmotic gradient in the medulla
What is the main function of the Distal convoluted tubule?
acid-base and water balance
=> fine-tuning the filtrate
What hormone controls reabsoprtion of Na in the distal convoluted tubule?
Aldosterone
What structures can be seen as stripes in the cortex that point toward the medulla?
Parallel bundles of collecting ducts
What name is often given to the largest part of a collecting duct?
Duct of Bellini
What hormone increases the permeability of the collecting duct to water?
Antidiuretic hormone
A high ADH causes more concentrated urine. TRUE/FALSE?
TRUE
think - diuretics get rid of peoples fluid
=> Antidiuretic hormone retains fluid (water)
=> urine produced is more concentrated
What epithelium is found in the urinary tract?
transitional epithelium or urothelium
What type of cells face the lumen of the urinary tract?
umbrella cells (due to domed appearance)
What size is the male urethra compared to the female urethra?
Male = 20cm Female = 3-5 cm
What types of epithelium are found in the female urethra?
Transitional epithelium until changing to squamous at termination
What types of epithelium are found in the male urethra?
Prostatic urethra = transitional epithelium.
Membranous urethra = Transitional changes to stratified columnar
Penile urethra = stratified columnar THEN stratified squamous
